Improve message when the cursor in pagination is invalid (saleor#8594)

saleor/graphql/core/connection.py

@@ -237,8 +237,12 @@ def connection_from_queryset_slice(
 
     requested_count = first or last
     end_margin = requested_count + 1 if requested_count else None
+
     cursor = after or before
-    cursor = from_global_cursor(cursor) if cursor else None
+    try:
+        cursor = from_global_cursor(cursor) if cursor else None
+    except ValueError:
+        raise GraphQLError("Received cursor is invalid.")
 
     sort_by = args.get("sort_by", {})
     sorting_fields = _get_sorting_fields(sort_by, qs)

saleor/graphql/core/tests/test_pagination.py

@@ -218,3 +218,14 @@ def test_pagination_backward_last_page_info(books):
     page_info = content["books"]["pageInfo"]
     assert page_info["hasNextPage"]
     assert page_info["hasPreviousPage"] is False
+
+
+def test_pagination_invalid_cursor(books):
+    cursor = graphene.Node.to_global_id("BookType", -1)
+    variables = {"first": 5, "after": cursor}
+
+    result = schema.execute(QUERY_PAGINATION_TEST, variables=variables)
+
+    assert result.errors
+    assert len(result.errors) == 1
+    assert str(result.errors[0]) == "Received cursor is invalid."